Show aditional WiFi calling message.

Bug: 37624313
Test: manual - locally apply this setting and verify that the
               additional text is shown.
Change-Id: I8a15a9aeb71a0daab1ae4533f2c3b7d05c57bc5f

src/com/android/settings/WifiCallingSettings.java

@@ -152,7 +152,9 @@ public class WifiCallingSettings extends SettingsPreferenceFragment
 
         mEmptyView = (TextView) getView().findViewById(android.R.id.empty);
         setEmptyView(mEmptyView);
-        mEmptyView.setText(R.string.wifi_calling_off_explanation);
+        String emptyViewText = activity.getString(R.string.wifi_calling_off_explanation)
+                + activity.getString(R.string.wifi_calling_off_explanation_2);
+        mEmptyView.setText(emptyViewText);
     }
 
     @Override